9th Experimental Archaeology Conference poster – McGoran
Casting into Open One Piece Moulds: Problems and Possible Solutions
Umha Aois has been running for twenty years, and amid a myriad of other casting experiments, we have poured into open moulds on numerous Symposia. At Umha Aois 2011, Killarney, County Kerry, we dedicated the Symposium to smelting copper ore, and also to pouring one piece open moulds. As a project, the smelting was a resounding success, but the successful pouring of an axe into an open mould remained elusive.
Prior to the event, we had visited the vaults of the N.M.I. in Dublin. I noted straight away the stone presented had several carvings that were twice as deep as the axes presented in museums. I mused upon this. At Killarney 2011 I carved several moulds fifteen millimetres deep, and then poured the moulds to half their capacity.
To my delight, I had a result. The top side had no sign of reticulation due to oxidation that previous attempts had manufactured, unfortunately, when the casting was turned over, it presented the same dreaded bubble in where had now been considered to be the usual place.
However, I still thought there was one final trick up my sleeve. We had tried covering the mould with straw immediately after pouring. I personally tried putting a straw near the bubble area thinking that would do the trick.
So then, it turns out that our ancient forebears had similar problems. I made contact with several Archaeologists who had previously participated on the Umha Aois Project. They have furnished me with examples of the bubble in antiquity, how fascinating to know that a simple trick solves these problems.